Mechanical

0ILUS

The design of this boat is inspired by military war ships. It is decorated with a dragon head, spiked encasing and cannons where the water is pumped out from.

The mechanical part of the 0ILUS is comprised of the main chassis, underwater propulsion system, and shooting mechanism, as discussed in the following sections.

Overall Design

The overall design occupies a dimension of 55 cm in length, 41 cm in width, and 50 cm tall. This is so that the boat stays within the guidelines of 6 feet circumference. The overall encasing, dragon head and cannons are decorations that were 3D printed with PLA from the PRL.

Front View

Side View

Front View

Side View

Chassis

The main body of the boat is constructed from laser cut 0.23'' acrylic sheets. Beneath the main chassis is a 2" thick layer of pink foam for buoyancy. Triangular wings on the side aid in additional stability. The entire boat is surrounded with a pool noodle that serves as the bumper in case the boat hits against walls, as well as providing buoyancy.

Mounted to the chassis of the boat are two 3D printed underwater thruster mounts that holds 2 underwater thrusters on each side. This serves as our propulsion system (more discussed in the following section). In front of the entire boat assembly consists of the shooting module. A pump is mounted onto the chassis with its inlet to extract water pointing through a hole in the chassis directly into the water, and its outlet curved forwards to shoot at opponents.

Behind the shooting module is the electronics module. All the electronics (PDB, Pic Boards, Motor Drivers etc) are housed in a clear, plastic food storage container to prevent water damage. This enclosure was designed to meet the IP-24 standard for liquid ingress, which states that liquid spray from any direction should not penetrate the enclosure. To provide more space for the pump, the electronics module sits on a 3D printed elevated mount that also serves to add distance from water exposure. Inside the box also contains mounts for the PDB and other electronics to sit more stable. Small holes were bored in the sides and top of the box for mechanical and electrical feedthrough ports. To mitigate the risk of these holes, hot glue was applied to seal these holes.

Propulsion System

The propulsion system consists of the control side from the electronics box as well as the underwater thrusters. The electronics side provide power and PWM for the thrusters to operate. This particular type of thrusters require the use of an ESC, or an electronic speed controller, that interprets the signals sent by the microcontroller to generate alternating three-phase current for the motors to operate. The underwater thrusters are operated at 40% duty cycle, so as to not draw too much current from the battery.

Shooting System

Similar to above, the shooting system consists of the control from the electronics box and a purchased, commerical off the shelf pump. The controls from the microcontroller turn the pump on and off, and vary the input duty cycle of the pump. The default setting of the pump was set to 50% duty cycle when turned on. To increase or decrease angles, the duty cycle was varied with a resolution of 5% duty cycle each time that it was pressed. The inlet of the pump to extract water was directly fed to the water through a hole in the chassis, while the outlet was routed to the front of the boat. This outlet was mounted onto a shooting base, with 4 cannons as decoration, in order to elevate the angle and provide a flat surface for the outlet to sit on. The angle of this shooting base was 45 degrees. Lastly, to shoot a more concentrated stream of water, the outlet of the pump was fed through a cone shaped nozzle. This nozzle was continuously iterated to achieve the desired concentrated stream of water.

NEDMO

The NEDMO comprises of the FUELCON and the NAVCON. These components remotely operate the 0ILUS.

The FUELCON was laser cut with 3/16'' duron and assembled together into a box enclosure, while the NAVCON was 3D printed.

FUELCON

The FUELCON is responsible for displaying the fuel status with messages that are sent by the 0ILUS. The dimensions of the FUELCON are 30 cm x 28 cm x 18 cm. It forms a box-like enclosure to store the electronics inside. A belt strap is mounted to the sides of the FUELCON so that the operator can wear it during the competition. In terms of assembly for the box, the base and side walls were aligned and placed together using metal L-brackets. The front lid acts as a separate removable panel with a latch mechanism, so that we could easily access the electronics and close the door to secure everything. There are extruded holes on the side of the box so as to feed wires through for the NAVCON.

The FUELCON consists of a DM Display that displays the 6 boats the user could choose from: 1 2 3 4 5 6. Using a joystick, the user can manually switch between the 6 boats to choose a different boat, and press the yellow button next to it to confirm selection. Upon selecting that boat, the display will only light up that one number to further indicate to the user which boat has been selected. To the right of the boat choosing is the fuel indicator status. This is an indicator servo that receives messages from the boat regarding fuel status, and displays them on the FUELCON. Each fuel increment is 20%, with a maximum of 100%. Lastly, the FUELCON also has a refuel drum button for refueling the boat. Per requirement, the user has to make a large scale action in order to refuel the boat. Our large scale action consists of using a plastic hammer to repeatedly hit the refuel button every 0.5s.

Dimension

Functionalities

NAVCON

In combination with the FUELCON, the NAVCON serves to control the 0ILUS. Its design is inspired by a game controller. Its dimensions are 19 cm x 5 cm x 10 cm, with a 3D printed encasing. The NAVCON uses a joystick to control the left, right, forwards and backwards orientation of the boat. As seen in the picture below, right corresponds to CW rotation of the boat while left corresponds to CCW rotation of the boat. Since other teams also employ the use of a rudder, our team had to strategically map our joystick controls to accommodate all teams. Lastly, the NAVCON also contains the buttons for the shooting mechanism. The red button corresponds to "shoot" which is to turn on the pump and shoot water at a default rate of 50% duty cycle. The upper button corresponds to increase angle of attack by 5% duty cycle, while the lower button corresponds to decrease the angle of attack by 5% duty cycle. Per our design, the user has to hold the shoot button while simutaneously pressing the lower/upper button in order to change the pump angle.

Dimension

Functionalities

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